1. Field of the Invention
The present invention relates to a switch device, more particularly, to a switch device suitable for an operating motor for driving, for example, a power window.
2. Description of the Related Art
Various types of switch devices have been manufactured according to various purposes in the related art. Of those switch devices, a switch device for driving a motor, mainly, a motor for a power window for a vehicle is disclosed in JP-A-2000-348569 (U.S. Pat. No. 6,191,372). FIGS. 5A and 5B are views showing the construction of a switch device according to the related art. FIG. 5A is a perspective view showing an operation member, and FIG. 5B is a cross-sectional view of a switch housing on which the operation member is mounted.
The switch device is constructed of a switch knob 102 mounted on a switch housing 110, and the switch housing 110 which is mounted on a panel 100 having a switch accommodation part 100a. Specifically, as a protrusion 100c extending outwardly from a wall 100b of the switch housing 110 is engaged with a hole 102a formed at a side wall of the switch knob 102, the switch knob 102 is mounted on the switch housing 110. In this switch device, by operating the switch knob 102 in a direction indicated by an arrow in FIG. 5A, the switch knob 102 seesaws about the engaged region as a fulcrum. Accordingly, a motor can be driven in the normal or reverse direction.
However, when a force is applied in an upward direction of the arrow shown in FIG. 5A, a front end 102b of the switch knob 102 is brought into contact with the surface of the switch housing 110. When a force is applied in a direction which lifts up a rear end 102c about a contact Y of the switch housing as a fulcrum, a large amount of force is applied on a region between the bottom surface of the protrusion 100c and a lower part of the inner peripheral surface partitioning the hole 102a, and accordingly, a slip therebetween occurs. Thus, the switch knob 102 is deformed so that the front end (opening end) of the switch knob 102 widens. Therefore, the protrusion 100c is disengaged from the hole 102a, and eventually, the switch knob 102 is disengaged from the switch housing 110.
Parts facing the protrusions 100c of the switch housing 110 can prevent the switch knob 102 from extending outward to some degree. However, the switch knob 102 is disposed at a free end side with respect of the switch housing 110, and thus the switch knob 102 can be easily deformed. Further, it is difficult to reliably prevent the switch knob 102 from extending outward since there are accuracy problems when the switch knob 102 is mounted on the switch housing 110. In this structure, there is also a problem in that formation of the panel 100 is limited.